Landscapes Forest and Global Change - ESA - Escola Superior ...

A.L. Teixido et al. 2010. Impacts of changes in land use and fragmentation patterns on Atlantic coastal forests
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Table 2: Landscape metrics of forest in Fragas do Eume Natural Park in 1957 and 2003. The absolute and
relative change of each landscape metric is also shown. Change values greater than 0 indicate gains, and
those less than 0 indicate losses
Landscape metric 1957 2003 Change 1957-2003
Absolute Relative (%)
Largest patch index (%) 32 11 -22 -34.4
Mean patch size ± SD (ha) 52 ± 344 19 ± 110 -33 -63.5
Total edge length (km) 367 484 +118 +32.1
Total core area (ha) 2,054 1,178 -876 -42.6
Largest patch core area (ha) 1,842 530 -1312 -71.2
Mean distance ± SD (m) 489 ± 315 641 ± 546 +152 +31.1
number of patches under 10 ha, and particularly those under 1 ha, increased from 1957 to 2003
and represented a higher proportion of the total number of patches.
There was an increase in total edge length and a decline in total core area and also a decline in
largest patch core area. Mean distance among patch edges increased 31%. Forest patches also
showed an increase of 32% in the total adjacency index between 1957 and 2003 (Table 2).
In 1957, a large proportion (89%) of total water course length was covered by riparian forests,
including the whole length of the Eume River (Fig. 2). In 2003, riparian forest length decreased
34%. Losses were associated to eucalypt plantations (11%), and mostly to the building of the
water reservoir (23%).
Figure 2: Changes in the spatial distribution of riparian forest in Fragas do Eume Natural Park
4. Discussion
Our results showed a high spatial heterogeneity in land cover over the whole area in both study
periods, with most land cover classes consisting of a large number of patches interspersed with
other different classes (Fig. 1). Land cover area comparisons and detailed transition analyses
showed that the landscape was highly dynamic over the 50-year period, mostly due to
intensification of exotic species plantations (especially eucalypt), farming abandonment and the
building of a water reservoir. Eucalypt plantations were mostly introduced in northern Spain
during the second half of the 20th century because of their high pulp productivity. Farming
abandonment also represented large landscape changes due to depopulation of these rural
lowlands during the second half of the 20th century (Calvo-Iglesias et al. 2006).
Forest Landscapes and Global Change-New Frontiers in Management, Conservation and Restoration. Proceedings of the IUFRO Landscape Ecology
Working Group International Conference, September 21-27, 2010, Bragança, Portugal. J.C. Azevedo, M. Feliciano, J. Castro & M.A. Pinto (eds.)
2010, Instituto Politécnico de Bragança, Bragança, Portugal.